Interstitial cystitis (IC) is a multifactorial syndrome, with several proposed etiologies. No clinical or histological factors are pathognomonic, and the diagnosis is essentially one of exclusion. A major problem with current IC research is the lack of objective markers for this symptom complex. The investigators' broad, long-term goals are to identify objective markers of IC, which will be valuable for many purposes. These include: (1) identifying subsets of IC patients with specific etiologies, (2) selecting patients for focused basic research on specific etiologies, (3) selecting patients for treatments directed towards specific etiologies, (4) testing whether the treatments truly are resolving the specific pathophysiologic processes. Since the etiologies of IC are still unknown, the best approach at this time is to seek associations between the proposed marker and other clinical/pathologic features of IC. Several urine components are known to be elevated in IC, and may be useful objective markers. Many of these markers are thought to reflect specific underlying pathophysiologies of IC. The markers include glycosaminoglycans, MUC-1 glycoprotein, hyaluronic acid, methylhistamine, interleukin-6, interleukin-8, cyclic GMP (a reflection of nitric oxide synthase), anti-proliferative factor, epidermal growth factor, heparin-binding epidermal growth factor-like growth factor, insulin-like growth factor and insulin-like growth factor binding protein 3. This study will test for associations between these urine markers and other features of IC, including an objective measurement of bladder permeability (Aims 1 and 2), symptom response to bladder distention (Aim 3) and relevant objective features of bladder biopsies (Aim 4). The ideal outcome will be to identify markers relevant to specific etiologies, which associate strongly with other markers relevant to the same etiologies. The markers with the strongest associations will be useful for future basic and clinical research directed towards specific etiologies of IC. This focused research will lead to improved, specific treatments for IC.